• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.459-462
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• 2000

The pretreatment of used newspaper for the enzymatic digestion preprocess was performed on a percolation reactor and a batch reactor. The test condition of percolation process was $170^{circ}C$, 60min, 1 mL/min, and 400psi, that of batch was $40^{circ}C$, 3hr. and latm Reaction solutions used in pretreatment process were aqueous ammonia, sulfuric acid, water, and hydrogen-peroxide as an oxidizing agent. As a result, the effect of pretreatment was similar to batch and percolation process, but the yield of enzymatic hydrolysis was higher in batch than percolation. This batch pretreatment enhanced enzymatic hydrolysis rate and increased glucose yield from about 15 to 20%. The inhibition factors influenced the rate of enzymatic hydrolysis was investigated, and the ink contented newspaper was the major factor.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.704-711
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• 2010

Lignocellulose ($2^{nd}$ generation) is difficult to hydrolyze due to the presence of lignin and the technology developed for cellulose fermentation to ethanol is not yet economically viable. However, recent advances in the extremely new field of biotechnology for the ethanol production are making it possible to use of agriculture residuals and nonedible crops biomass, e.q., rice straw and miscanthus sinensis, because of their several superior aspects as agriculture residual and nonedible crops biomass; low lignin, high contents of carbohydrates. In this article, as the basic study of AP(Ammonia Percolation), the properties and the optium conditions of process were established, and then the overall efficiency of AP was investigated. The important independent variables for AP process were selected as ammonia concentration, reaction temperature, and reaction time. The percolation condition for maximizing the content of cellulose, the enzymatic digestibility, and the lignin removal was optimized using RSM(Response Surface Methodology). The determined optimum condition is ammonia concentration; 11.27%, reaction temperature; $157.75^{\circ}C$, and reaction time; 10.01 min. The satisfying results were obtained under this optimized condition, that is, the results are as follows: cellulose content(relative); 39.98%, lignin content(relative); 8.01%, and enzymatic digestibility; 85.89%.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.303-307
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• 2013

This study compares the efficacy of soaking and percolation pretreatments with alkaline solutions for lignocellulosic biomass. Various biomass such as rice straw and barley were pretreated by soaking processes in various alkaline solutions including sodium hydroxide, potassium hydroxide, aqueous ammonia and sodium carbonate. The enzymatic digestibility of rice straw and barley that had been pretreated by soaking in aqueous ammonia was over 80%. Eucalyptus residue, Larix leptolepis and Pinus rigida exhibited relatively low enzymatic digestibility. Nevertheless, the enzymatic digestibility of pretreated eucalyptus residue was increased by five times compared to that of the initial biomass. And, the enzymatic digestibility of the percolation pretreated eucalyptus residue was increased 12 times.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.89-95
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• 2009

Because of high contents of cellulose (~37 wt%) and hemicellulose (~17%), rice straw seems to be a potential lignocellulosic biomass for production of bioethanol. In this study, Ammonia Recycled Percolation (ARP) pretreatment of rice straw was extensively investigated. In particular, the experimental study included the effects of temperature, reaction time and concentration of ammonia on compositions and enzymatic digestibility of the resulting solid residues; the ranges of pretreatment conditions were, in turn, $150{\sim}190^{\circ}C$, 10~90 min and 0~20 wt%. Through ARP pretreatment, the lignin content was reduced by as high as ~84% while 20~80% of the hemicellulose was also solubilized. The solid residue resulted from the pretreatment with 15 wt% aqueous ammonia solution at $170^{\circ}C$ for 90 mim showed as high as ~90% of digestibility with 15FPU/g of glucan enzyme loading. Supplement of xylanese to cellulase led to a notable enhancement of digestibility, indicating a discernable inhibitory role of hemicellulose. Simultaneous Saccharification and Fermentation (SSF) and Simultaneous Saccharification and Co-Fermentation (SSCF) were performed to obtain ethanol productions of 13.8 g/L (corresponding to 81% yield) and 15 g/L (corresponding to 89% yield), respectively.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.126-126
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• 2003

• KSBB Journal
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• v.14 no.3
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• pp.358-364
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• 1999

The effect of hydrogen peroxide on pretreatment of oakwood was investigated. Reaction temperature was $170^{\circ}C$ and reaction solutions used in pretreatment were aqueous ammonia, sulfuric acid and pure water. When 10% ammonia solution was used, the extents of delignification and hemicellulose recovery were 55% and 26%, respectively. These values were significantly higher as delinigfication and lower as hemicellulose recovery than those of acid hydrolysis. To overcome this problem, hydrogen peroxide was added into ammonia solution stream to increase hemicellulose recovery. But delignification and hemicellulose recovery were not increased as much as hydrogen peroxide loading was increased. And as hydrogen peroxide loading was increased, the decomposition of sugars solubilized from hemicellulose and cellulose were increased. So there were significant differences between the total amount in solid residue and liquid hydrolyzate, and the total amount in the original biomass. It was found that hydrogen peroxide added was reacted with substrate packed mostly in the front part of reactor. In order to increase hemicellulose recovery, it was necessary to treat with acidic solution than with alkali solution. Effect of hydrogen peroxide was higher in water than acid solution.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.45-51
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• 2014

This is to study the effects of various pretreatment methods of agricultural residue, corn stover, and to compare the feature and pros and cons of each method including dilute sulfuric acid (DSA), soaking in aqueous ammonia (SAA), and ammonia recycle percolation (ARP). In order to convert corn stover to ethanol, various pretreatments followed by simultaneous saccharification and co-fermentation (SSCF) were tested and evaluated in terms of ethanol yield. With 3%, w/w of glucan loading using ARP-, DSA-, and SAA-treated solids, SSCFs using recombinant E. coli strain (ATCC$^{(R)}$ 55124) with commercial enzymes (15 FPU of Spezyme CP/g-glucan and 30 CBU/g-glucan enzyme loading) were tested. In the SSCF tests, 87, 90, and 78% of theoretical maximum ethanol yield were observed using ARP-, DSA-, and SAA-treated solids, respectively, which were 69, 58, and 74% on the basis of total carbohydrates (glucan + xylan) in the untreated corn stover. Ethanol yield of SAA-treated solid was higher than those of ARP- and DSA-treated solids. In addition, SSCF test using treated solids plus pretreated hydrolysate indicated that the DSA-treated hydrolysate showed the strongest inhibition effect on the KO11 strain, whereas the ARP-treated hydrolysate was found to have the second strongest inhibition effect. Bioconversion scheme using SAA pretreatment and SSCF can make the downstream process simple, which is suggested to produce ethanol economically because utilization of hemicellulose in the hydrolysate is not necessary.

• KSBB Journal
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• v.16 no.5
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• pp.446-451
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• 2001

A pretreatment method to increase enzymatic digestibility for waste paper such as newspaper was investigated. Ash content, substrate size and printed ink were considered to be factors that affect on enzymatic hydrolysis. The effect on enzymatic digestibility of varying these factor were measured. Printed ink had the highest effect of the three factors, so a method was developed to remove the ink during pretreatment. Fist, a pretreatment process using a percolation reactor was tried. The digestibility of the substrate pretreated at 170$\^{C}$, however, was less than that of the untreated substrate because only small portion of ink was removed. Therefore, a batch type process at less than 100$\^{C}$ was devised. Of several schemes, a method using amonia-hydrogen peroxide mixture on a shaking bath proved most effective. The digestibility obtained from this method was about 85%--approximately 20% greater than the untreated substrate. This proves the pretreatment method was very effective in treating waste paper. The high digestibility obtained from this pretreatment is probably due to the effects of the hydrogen peroxide that can enhance ink removal and substrate swelling.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.1-5
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• 2015

Lactic acid, the most widely occurring hydroxy-carboxylic acid, has traditionally been used as food, cosmetic, pharmaceutical, and chemical industries. Even though it has tremendous potential for large scale production and use in a wide variety of applications, high cost lactic acid materials are primarily problems. Lactic acid can be obtained on either by fermentation or chemical synthesis. In recent years, the fermentation approach has become more successful because of the increasing market demand for naturally produced lactic acid. Generally, lactic acid was produced from pure starch or from glucose. As an alternative, biomass which is the most abundant renewable resources on earth have been considered for conversion to readily utilizable hydrolysate. In this study, we conducted the fermentation method to produce L(+)-lactic acid production from pretreated hydrolysate was investigated by Lactobacillus rhamnosus ATCC 10863. The hydrolysate was obtained from pretreatment process of biomass using Ammonia percolation process (AP) followed by enzymatic hydrolysis. In order to effectively enhance lactic acid conversion and product yield, controlled medium, temperature, glucose concentration was conducted under pure glucose conditions. The optimum conditions of lactic acid production was investigated and compared with those of hydrolysate.